The present invention relates to an electronically controllable brake actuating system for automotive vehicles which includes a master brake cylinder operable by an actuating pedal and having at least one piston, at least one braking pressure generator actuatable by an electronic control unit, to which braking pressure generator wheel brakes of the vehicle are directly connected and which is connectable to the master brake cylinder by at least one hydraulic connection closable by a valve assembly, at least one sensor device to identify the driver's wish for deceleration, and a simulator chamber which interacts with the master brake cylinder.
A brake actuating system of this type is disclosed in applicant's former application No. 44 13 579. In the prior art brake actuating system, two simulator chambers are associated with the pressure chambers of the master brake cylinder that is configured as a tandem master brake cylinder. The simulator chambers are connected to the pressure chambers by the intermediary of a parallel combination of an electrically actuatable, preferably normally closed (NC) two-way/two-position directional control valve and a non-return valve which opens towards the master brake cylinder.
A disadvantage in the prior art brake actuating system is that the electromagnetically operable two-way/two-position directional control valves, which must be energized with each activation of the system, become frequently leaky in operation and, thus, are a potential source of malfunction.
Therefore, an object of the present invention is to provide an improved electronically controllable brake actuating system of the type referred to hereinabove in terms of an enhanced reliability in operation. In addition, the circuit arrangement of a system of this type shall be simplified considerably.